Jesus was born years earlier than thought, claims Pope The entire Christian calendar is based on a miscalculation, the Pope has declared, as he claims in a new book that Jesus was born several years earlier than commonly believed.

The 'mistake' was made by a sixth century monk known as Dionysius Exiguus or in English Dennis the Small, the 85-year-old pontiff claims in the book 'Jesus of Nazareth: The Infancy Narratives', published on Wednesday.

"The calculation of the beginning of our calendar – based on the birth of Jesus – was made by Dionysius Exiguus, who made a mistake in his calculations by several years," the Pope writes in the book, which went on sale around the world with an initial print run of a million copies.

"The actual date of Jesus's birth was several years before."

The assertion that the Christian calendar is based on a false premise is not new – many historians believe that Christ was born sometime between 7BC and 2BC.

But the fact that doubts over one of the keystones of Christian tradition have been raised by the leader of the world's one billion Catholics is striking.